Abstract
The standard laminar proportional amplifiers (LPA's)developed in USA can not obtain high power gains, because the output oscillates at large supply flow rate. In this paper, then the effects of the various geometrical parameters on the pressure gain and the operating flow rate range of LPA are experimentally investigated to find the optimum dimensions of LPA giving higher pressure gain and wider operating range.
The results obtained from this study are as follows:
(1) The pressure gain is affected by the control nozzle width, the width of throat between control ducts, the distance between vent vanes, and the receiver distance from supply nozzle. The increase of the control nozzle width results in an increase in the pressure gain, but the increase of the distance between vent vanes or the increase of the receiver distance from supply nozzle results in a decrease in the pressure gain. The optimal dimension of the width of throat between control ducts for high pressure gain is 1.5 times the supply nozzle width.
(2) Operating range is affected by the length of vent ducts and the distance from supply nozzle to receiver. Shortening the length of vent ducts extends the operating range. As the distance from supply nozzle to receiver increases, the output oscillates even at rather low flow rate.
(3) The maximum pressure gain does not depend on the aspect ratio. The maximum supply power without output oscillation increases with the decrease in aspect ratio.
